release/src-rt-6.x.4708/linux/linux-2.6.36/arch/sh/mm/ioremap.c

   1 /*
   2  * arch/sh/mm/ioremap.c
   3  *
   4  * (C) Copyright 1995 1996 Linus Torvalds
   5  * (C) Copyright 2005 - 2010  Paul Mundt
   6  *
   7  * Re-map IO memory to kernel address space so that we can access it.
   8  * This is needed for high PCI addresses that aren't mapped in the
   9  * 640k-1MB IO memory area on PC's
  10  *
  11  * This file is subject to the terms and conditions of the GNU General
  12  * Public License. See the file "COPYING" in the main directory of this
  13  * archive for more details.
  14  */
  15 #include <linux/vmalloc.h>
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <linux/mm.h>
  19 #include <linux/pci.h>
  20 #include <linux/io.h>
  21 #include <asm/page.h>
  22 #include <asm/pgalloc.h>
  23 #include <asm/addrspace.h>
  24 #include <asm/cacheflush.h>
  25 #include <asm/tlbflush.h>
  26 #include <asm/mmu.h>
  27
  28 /*
  29  * Remap an arbitrary physical address space into the kernel virtual
  30  * address space. Needed when the kernel wants to access high addresses
  31  * directly.
  32  *
  33  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
  34  * have to convert them into an offset in a page-aligned mapping, but the
  35  * caller shouldn't need to know that small detail.
  36  */
  37 void __iomem * __init_refok
  38 __ioremap_caller(phys_addr_t phys_addr, unsigned long size,
  39                  pgprot_t pgprot, void *caller)
  40 {
  41         struct vm_struct *area;
  42         unsigned long offset, last_addr, addr, orig_addr;
  43         void __iomem *mapped;
  44
  45         /* Don't allow wraparound or zero size */
  46         last_addr = phys_addr + size - 1;
  47         if (!size || last_addr < phys_addr)
  48                 return NULL;
  49
  50         /*
  51          * If we can't yet use the regular approach, go the fixmap route.
  52          */
  53         if (!mem_init_done)
  54                 return ioremap_fixed(phys_addr, size, pgprot);
  55
  56         /*
  57          * First try to remap through the PMB.
  58          * PMB entries are all pre-faulted.
  59          */
  60         mapped = pmb_remap_caller(phys_addr, size, pgprot, caller);
  61         if (mapped && !IS_ERR(mapped))
  62                 return mapped;
  63
  64         /*
  65          * Mappings have to be page-aligned
  66          */
  67         offset = phys_addr & ~PAGE_MASK;
  68         phys_addr &= PAGE_MASK;
  69         size = PAGE_ALIGN(last_addr+1) - phys_addr;
  70
  71         /*
  72          * Ok, go for it..
  73          */
  74         area = get_vm_area_caller(size, VM_IOREMAP, caller);
  75         if (!area)
  76                 return NULL;
  77         area->phys_addr = phys_addr;
  78         orig_addr = addr = (unsigned long)area->addr;
  79
  80         if (ioremap_page_range(addr, addr + size, phys_addr, pgprot)) {
  81                 vunmap((void *)orig_addr);
  82                 return NULL;
  83         }
  84
  85         return (void __iomem *)(offset + (char *)orig_addr);
  86 }
  87 EXPORT_SYMBOL(__ioremap_caller);
  88
  89 /*
  90  * Simple checks for non-translatable mappings.
  91  */
  92 static inline int iomapping_nontranslatable(unsigned long offset)
  93 {
  94 #ifdef CONFIG_29BIT
  95         /*
  96          * In 29-bit mode this includes the fixed P1/P2 areas, as well as
  97          * parts of P3.
  98          */
  99         if (PXSEG(offset) < P3SEG || offset >= P3_ADDR_MAX)
 100                 return 1;
 101 #endif
 102
 103         return 0;
 104 }
 105
 106 void __iounmap(void __iomem *addr)
 107 {
 108         unsigned long vaddr = (unsigned long __force)addr;
 109         struct vm_struct *p;
 110
 111         /*
 112          * Nothing to do if there is no translatable mapping.
 113          */
 114         if (iomapping_nontranslatable(vaddr))
 115                 return;
 116
 117         /*
 118          * There's no VMA if it's from an early fixed mapping.
 119          */
 120         if (iounmap_fixed(addr) == 0)
 121                 return;
 122
 123         /*
 124          * If the PMB handled it, there's nothing else to do.
 125          */
 126         if (pmb_unmap(addr) == 0)
 127                 return;
 128
 129         p = remove_vm_area((void *)(vaddr & PAGE_MASK));
 130         if (!p) {
 131                 printk(KERN_ERR "%s: bad address %p\n", __func__, addr);
 132                 return;
 133         }
 134
 135         kfree(p);
 136 }
 137 EXPORT_SYMBOL(__iounmap);